Fluid delivery apparatus



Jan. 13, 1959 E. v. PARKER 2,868,131

FLUID DELIVERY APPARATUS Filed Jan. 51, 1955 INVENTOR fF/VEZST l/ BAR/(ER I ATTORNEYS Jan. 13, 1959 2 Sheets-Sheet 2 Filed Jan. 31, 1955 R M W M w 5 0 Z? 6 mfl 3X m w i w 2 4 4 llll. i 1 I Z H w, e w a; T 4 W i 2 8 6 H ll.

United States atent 2,868,131 I FLUID DELIVERY APPARATUS Ernest V. Parker, Oakland, Calif. Application January 31, 1955, Serial No. 485,002

Claims. (Cl. 103- 41) The present invention relates generally to apparatus for providing a high pressure fluid and for controllably delivering sameas may be employed in fuel injection for diesel engines and the like. i

The invention hereinafter described is an'improvement upon the apparatus set out in my Patent No. 2,174,526 and reference is made thereto for the difliculties of high pressure fuel injection. The objects of the present invention generally include those of my above noted patent and in addition include more specific objects as follows:

It is an object of the present inventionto provide high pressure fluid delivery apparatus successively providing at separate points high pressure fluid maintained at a substantially constant pressure at the delivery points during delivery thereof.

It is a further object of the present invention to provide apparatus for high pressure fuel. injection including a single fluid accumulator for separate groups of delivery points together with means maintaining accumulator pressure constant during fluid delivery.

It is still a further object of the present invention to provide an improved and simplified scroll regulator in fluid delivery apparatus. p

The invention possesses other objects and features of advantage, some of which, with the foregoing, will be set forth in the following description of the preferred form of the invention which is illustrated in the drawing accompanying and forming part of the specification. It is to be understood, however, that variations in the showing made by the said drawing and description may be adopted within the scope of the invention as set forth in the claims.

The invention is illustrated in the accompanying drawing wherein: V

Figure 1 is a plan view of fluid delivery apparatus having parts broken away as indicated to show a single pump and control means in section.

Figure 2 is an enlarged partial sectional view of the apparatus taken at 2-2 of Figure 1.

Figure 3 is a sectional view taken at 33 of Figure 2 and showing the pumpof Figure 1 viewed in the opposite direction.

Figure 4 is a transverse sectional view taken at 4'4 of Figure 3.

The fluid delivery apparatus of the present invention, as shown in the accompanying drawings, comprises a plurality of fluid pumps 11 with each including an elongated piston 12 disposed within a cylindrical chamber or cylinder 13 formed'by the longitudinal bore of a sleeve 14. The pumps 11 are adapted to provide fluid such as diesel oil to individually connected injectors or nozzles 16 from a common fuel line 17. In order to maintain a' steady oil pressure at the nozzles during their successive pulsed operation there is provided for each group of nozzles 16 and their associated pumps 11 an accumulator 18, all of which. are interconnected in a manner noted below. A

It is contemplated by the present invention that one accumulator 18 will be provided for each pump or a group of say three injector nozzles 16 in a diesel engine and that each of the noz'zles shall be connected thereto during fuel injection through the nozzle. This is readily accomplished by the provision of a single block 19 within which a chamber is formed to comprise the accumulator and which block also contains passages connecting the inlet three pumps. The sleeves or cylinder walls 14 of the pumps 11 each extend into the block 19 in spaced parallel relation and there is formed about the sleeves adjacent their inner ends chambers 21 which are interconnected and joined to the fuel line 17. Considering the pump illustrated in detail in Figure 1 and in Figures 2 and 3 there will be seen to be provided a plurality of transverse openings 22 through the cylinder wall or sleeve 14 into the fuel chamber 21 for the entry of fuel into the cylinder 13 above the piston 12. Pressurization and discharge of the fuel is accomplished by reciprocation of the piston 12 in a manner set out below and upward movement of the piston closes off the fuel inlet openings 22 with a. subsequent compression of the fuel above the piston 12. Discharge occurs through a central passage 23 extending from the top of the piston a distance into the piston and thence radially outward in opposite directions into separate communication with two separate slanted grooves on the piston surface and together comprising a scroll 24, as shown in Figures 3 and 4. A port 26 in one side of the cylinder Wall 14 is adapted for registry with the scroll 24 in the raised position of the piston and this injection or discharge port 26 forms the terminus of a passage 27 in the sleeve and block leading to a valve 28' that in turn connects by a line 29 to the nozzle or injector 16 associated with this pump described. Diametrically opposite the port 26 which leads to the injector is another port 31 communicating directly with the fuel inlet chamber 21 or other low pressure fuel depository whereby high pressure fuel may be readily discharged thereto. This relief port 31 is also adapted for full or partial registry with the scroll 24 although not at exactly the same point of registry of the scroll with the injection port 26 because of the scroll incline. The scroll 24 includes two separate grooves on the piston surface with each extending almost degrees thereabout and these groves are inclined longitudinally of the piston, as shown, with each separately communicating with the passage 23 to the top of the piston. Thus the rotational disposition of the piston determines the degree of registry of each scroll groove with its respective port 26 or 31 at any point on the piston stroke so that it remains but to position the piston rotationally to fix the relative registry of the scroll with the injector and relief ports so as to control the amount of fuel directed to the injector with each stroke or reciprocation of the piston 12.

The accumulator 18 is connected to the cylinder 13 at the head end thereof above the piston 12 and this connection is made through a valve 32 which operates to maintain a predetermined pressure in the accumulator and to connect same to the cylinder when this pressure is attained therein.

The valve 32 includes a cylinder 33 disposed in an aperture in: the block 19 with an axial bore having a piston 34 slidably disposed in the cylinder bore. The upper end of the piston 34 has a reduced diameter to define a shoulder about the piston and a tapered end comprising a valve head adapted to mate with a valve seat formed abo'uta reduced diameter bore in the cylinder end which together with a-bore in the block 19 forms a passage 35 to theaccumulator. The cylinder bore is enlarged on the piston side of the valve seat to form a chamber 36 which is closed at the lower end by the piston shoulder and a passage 37 in the cylinder 33 and block 19 communicates between this chamber 36 and the top of the pump piston 12 so that vertical motion of the piston 34 operates to connect and disconnect the accumulator 18 to the pump 11 above the piston 12 thereof.

The valve cylinder 33 is held in position within the block 19 by a sleeve 38 having a hollow upper end fitting about the cylinder and threaded into the block 19. A central internal flange 39 in the sleeve 38 engages the lower end of the cylinder 33 to hold same in position. A plug 40 having a hollow cylindrical upper end is threaded into the lower end of the sleeve 38 and a rod 41 extends vertically through the plug 40 in slidable relation thereto. The valve 32 is maintained normally closed by spring 42 compressed between exposed ends of the piston 34 and the rod 41 within the sleeve 38. The rod 41 is vertically adjustable by external means, not shown, for setting the spring pressure which maintains the valve normally closed and vertical motion of the piston 34 is limited by the internal sleeve flange 39 below same to a small valve opening of say .015 inch for example whereby rapid valve action and elimination of overtravel results.

Operation of the above described accumulator valve 32 is quite simple in that the valve is normally closed by the spring 42 seating the piston 34 and pressure from the accumulator acts upon the small end of the piston while the chamber 36 above the piston shoulder is at all times connected to the pump 11 above the piston 12 thereof. As the pump pressure increases sufliciently during the compression stroke thereof the pressure upon the shouder of the piston forces the piston downward to unseat the valve whereby the accumulator 18 is directly connected to the pump discharge. Following valve opening fluid flows into the accumulator during the period of increasing pump pressure and subsequently flows therefrom back to the pump to prevent pressure reduction thereat during injection so that a substantially constant pump discharge pressure is maintained. As the pump pressure falls below the predetermined accumulator pressure as set by the valve spring 42 the valve reseats to maintain the accumulator pressure.

Referring again to the pump 11 and considering the structure and actuation and control thereof it will be seen that the sleeve 14 forming the cylinder wall is disposed within an aperture within the block 19. The sleeve 14 has a centrally located shoulder thereabout against which a member 46 bears and this member engages the under block surface. An aperture in the member 46 accommodates the lower sleeve portion extending therethrough and a gear 47 is mounted for rotation about this lower sleeve portion. The pump 11 is spring loaded to return under spring pressure to a retracted position and to this end a spring 48 is disposed about a lower piston extension with a retaining ring at the top of the spring bearing against the member 46 and the bottom engaging a flange at the upper end of a push rod 49 secured to the lower end of the piston. Timed actuation of the pump is brought about by a cam shaft 51 mounted for rotation in a housing 52 secured to and supporting the block 19, said shaft having a plurality of spaced cams 53 thereon aligned to engage the push rods of each of the pumps 11. The cams 53 are rotationally displaced from one another in a well known manner and a roller 54 mounted at the bottom of the push rod 49 for rotation in a plane perpendicular to the axis thereof rides upon the surface of the cam 53. Rotation of the cam shaft 51, by means not shown, thereby rotates the cams 53 thereon and' the rollers 54 riding upon the cam surface forces the push rod 49 to complete one upward stroke for each turn of the cam shaft and as the piston 12 is secured to the upper end of the push rod 49, the piston likewise reciprocates within the cylinder under the dictate of the rotating cam shaft and cam 53 thereon. The spring 48 urges the push rod and attached piston downward so that the roller 54 maintains rolling contact with the cam surface. I

As noted above, the amount of fuel delivered to the injector 16 by each stroke of the piston is determined by the rotational disposition of the piston, for the scroll 24 thereon thereby registers with the relief port 31 and injection port 26 at a controllable predetermined point on the piston travel. The two grooves of the scroll 24 each extend almost degrees about the piston circumference so that the piston may be rotated almost 180 degrees and yet cause the injector port 26 for example to register with the same scroll groove although at different points on the piston stroke. The scroll grooves are both slanted in the same direction longitudinally of the piston so that from an intermediate rotational piston position rotation of the piston in one direction will cause groove-injector port registry sooner in the piston stroke than groove-relief port registry and reverse rotation will produce opposite results. Rotation of the piston to control the relative volume of fuel flow through the injector and relief ports may be accomplished in a variety of ways and there is illustrated for this purpose a rack 56 mounted for reciprocation below the block 19 within the housing 52. An idler gear 57 is mounted for rotation in toothed engagement with the gear 47 about the sleeve 14 and with a toothed surface of the rack 56. Attachment of the gear 47 to the piston is made by means of a radially extending key 58 afiixed to the lower end of the piston and reciprocally mounted in a split sleeve 59 depending from the gear. As the gear 47 is mounted for rotation about the cylinder wall sleeve 14, reciprocation of the rack 56 rotates the key 58 and thence the piston. The rack 56 may be reciprocated by conventional governor apparatus or in the case of variable speed motors a manual control may be provided therefore through appropriate linkage to a position convenient to the operator.

Operation of the invention follows directly from the foregoing description of the elements and connections thereof and in summary thereof and considering the flow of fluid such as fuel through one pump thereof it will be seen that fuel enters the chamber 21 through the inlet line 17 either from a pump or by gravity feed with suitable pressure relief means therein. With the piston 12 in a retracted position fuel enter the cylinder 13 above the piston through the ports 22 and as the piston travels upward these ports are closed thereby. The fuel above the piston is compressed until the pressure thereof becomes sufficient to open the valve 32 to the accumulator whereupon fuel flows into the accumulator 18. As the piston reaches a point where the scroll 24 thereon communicates with the injector port 26 high pressure fuel flows from the top of the piston downward through the central passage 23 therein and thence through the injector port 26 and the passage 27 to the valve 28. The fuel pressure in passage 27 raises the valve head to open valve 28 so the fuel flows through the line 29 to the injector which conventionally includes a valve and nozzle so that the fuel raises the valve to spray through the nozzle into the combustion chamber of the engine. As the piston continues to rise the direction of fuel flow reverses to flow from the accumulator 18 to the injector and maintain the pressure thereat. As the scroll 24 makes registry between the slanted groove thereof and the relief port 31 to the inlet chamber 21 fuel also flows from atop the piston back into the fuel inlet line so as to thereby limit the volume of fuel delivered to the injector during each piston stroke. Clearly the rotational position of the piston determines the relative registry of the scroll 24 with the injector port 26 and the relief port 31 during each piston stroke and thereby controls the volume of fuel injected during each stroke. As the fuel pressure atop the piston commences to fall at the top of the stroke the valve 32 closes by spring pressure to maintain a minimum accumulator pressure and also the injector valve closes. The fuel pressure to the injector starts at a high value and maintains same within very c ose limits until it abruptly drops at the end of. the

piston stroke with a pressure variation of a few percent at most during fuel injection with a consequent advantageous effect upon engine operation.

As was previously noted, the present invention is adapted for one or a group of injectors and there are illustrated three injectors connected to a single block wherein one accumulator is defined to serve all three injectors. Thus the accumulator is large enough to effectively maintain a substantially constant fuel pressure at each nozzle during injection and yet not to acquire the difficulties attendant conventional rail systems of injection.

What is claimed is:

1. Fluid delivery apparatus comprising a fluid pump including a movable piston Within a cylinder and a discharge passage controllably communicating with the cylinder atop said piston, means defining an accumulator chamber, a spring-loaded differential valve having a discharge side connected to said accumulator whereby pressure therein urges said valve open, means defining a conduit from said cylinder atop said piston to said valve at the inlet thereof, and said valve having an area above the head thereof adapted to be acted upon by fluid pressure in said conduit to urge said valve open whereby compression of fluid in said cylinder by said piston connects said accumulator to said cylinder and to the discharge passage therefrom for initially pressurizing same and subsequently discharging same for maintaining a substantially constant fluid discharge pressure.

2. Fluid delivery apparatus comprising a plurality of fluid pumps controllably connected to separate fluid discharge means, said pumps each having fluid inlet and outlet ports and being adapted to receive low pressure fluid through the inlet ports and to discharge high pressure fluid through the outlet ports of which one of each pump is connected to its respective fluid discharge means, means defining an accumulator chamber in flow communication with the pressure end of each of said pumps, and a plurality of differential valves interposed between said accumulator and each of said pumps whereby predetermined pump pressure opens the valve associated with the pump producing the pressure to connect the accumulator to the fluid discharge means of that pump for pressurizing said accumulator and holding said valve open by accumulator and pump pressure for maintaining fluid pressure at said discharge means substantially constant for a predetermined period.

3. Fuel delivery apparatus comprising a fluid pump having an inlet port and outlet ports, a discharge line connected to one of said outlet ports and adapted for connection to high pressure fluid apparatus, means defining a chamber connected to the other of said outlet ports, means controllably interconnecting the discharge side of said pump ano said outlet ports for controlling fluid pressure and volume delivered to said discharge line, means defining an accumulator chamber of substantial volume greater than the displacement of said fluid pump, and differential valve means connecting said accumulator chamber and the discharge side of said pump and providing communication therebetween at predetermined minimum pump pressure for initially charging said accumulator and subsequently partially discharging same whereby discharge pressure is maintained substantially constant for the period said differential valve is open.

4. Fluid delivery apparatus comprising a fluid pump having fluid inlet and outlet means ad including a high pressure chamber controllably communicating with said outlet means, means defining an accumulator chamber, and a normally-closed spring-loaded valve having a valve head and a shaft attached thereto with an expanded shaft section adjacent said head, said valve being connected to said accumulator chamber with the valve head facing same and connected to said pump high pressure chamber above the expanded shaft section whereby pump fluid pressure acts upon said expanded shaft section and said valve opens in response to a predetermined pump pressure to interconnect said accumulator chamber for charging said accumulator and maintaining a constant pump discharge pressure therefrom for a period determined by the spring pressure of said valve and pump discharge chamber.

5. Fluid delivery apparatus comprising a plurality of reciprocating fluid pumps with each having outlet means adapted for connection to individual high pressure fluid means at predetermined and controllable portions of pump stroke, means defining a single accumulator chamber, and a plurality of differential valves connected one to the discharge side of each pump and to said accumulator chamber, said valves being spring loaded to normally remain closed and being oriented to receive pump pressure in opposition to spring pressure for opening in response to a predetermined pump pressure, whereby said accumulator chamber, said discharge side of said pump and said outlet may all be placed in flow communication.

References Cited in the file of this patent UNITED STATES PATENTS 

